The slope of a line is a number that tells us how steep the line is. Lines with positive slope go up from left to right, whereas negative slope go down from left to right. The slope number is found by doing the ratio of vertical change on top of horizontal change, which is often referred to as rise over run or change in y over change in x. If a graph of a line is given, we can count the slope by drawing a "slope triangle" the connects two good points on the line and counting the vertical and horizontal changes. The y-intercept of a line is the point at which the line crosses the y axis. In an equation of the form y = mx + b, the m value is the slope and the b value is the y-intercept. We can use these two values to quickly draw the graph of a line.